Plates having electromagnetic-wave shielding property and light transmission properties have been developed as front filters of equipment such as office automation equipment and communication equipment in order to shield electromagnetic wave produced from such equipment. Such plates have been also utilized as window sheets of places where a precision apparatus is installed, such as a hospital and a laboratory, in order to protect the precision apparatus from electromagnetic waves for example from cellular phones.
A conventional electromagnetic-wave shielding and light transmitting plate typically comprises a pair of transparent substrates such as acrylic boards and a conductive mesh member like a wire netting or a transparent conductive film and is formed by interposing the conductive mesh member or the transparent conductive film between the transparent substrates and uniting them.
A conductive mesh member employed in the conventional electromagnetic-wave shielding and light transmitting plate is a 5- to 500-mesh member having a wire diameter of from 10 to 500 μm and an open area ratio (open area percentage) of less than 75%. The open area ratio is calculated from the wire diameter of mesh and the number of wires existing within a width of 1 inch. The electromagnetic-wave shielding and light transmitting plate employing such a conductive mesh member has low light transmittance of 70% at the most.
Moreover, such a conventional conductive mesh member easily allows the occurrence of moiré phenomenon due to relations between its patterns and the pixel pitch of a luminescent panel to which the electromagnetic-wave shielding and light transmitting plate is attached.
As means for satisfying the light transmitting property and the electromagnetic-wave shielding property simultaneously, it is considered to use a transparent conductive film instead of the conductive mesh member. In case of the transparent conductive film, however, it is difficult to achieve electric conduction relative to a panel body.
In case of the conductive-mesh member, by designing the conductive mesh member to have margins out of the peripheries of the transparent substrate and folding the margins, the electric conduction between the folded margins and the panel body is achieved. If the transparent conductive film is designed to have margins out of the transparent substrate and the margins are folded, the film may be torn at the folded portions.